Краткое описание

Heat transfer during condensation of a saturated vapor on a cylindrical tube in zero gravity is considered in connection with the development of cooling sys¬tems for cryogenic fuel tanks. A simple quasi-steady model of the process with a fixed interface temperature was developed earlier (Ajaev & Cherkasov, 1995). In the present study we consider a more general heat exchange model which takes into account unsteady effects, vapor recoil and thermocapillarity. The problem-is reduced to a single evolution equation, which provides a self-consistent descrip¬tion of the long-wave instabilities and their influence on the heat exchange in the system. It is proved analytically that the instabilities can be suppressed if the film thickness is smaller than a certain critical value. We also study the dependence of this critical thickness on different physical parameters. It is shown that the mass flux through the interface and thermocapillary tend to stabilize the film, but vapor recoil has a destabilizing effect.